The present invention relates to a one-part cold crosslinking emulsion composition employed in the fields such as coatings, adhesives, fiber processing, civil engineering and the like and a method of manufacturing the same.
Since aqueous emulsions in general are superior in terms of safety and hygiene to solvent type resins, they are widely used in the fields such as coatings, adhesives, fiber processing, civil engineering and the like. However, films using aqueous emulsion have problems of inferiority in water resistance, permeability to base material, impregnation-reinforcing property, surface smoothness and the like to films using the solvent type resins. Hence, in order to improve such aqueous emulsions, a method has been proposed of enhancing permeability to base material and surface smoothness by lowering a molecular weight of polymers so as to produce fluidity and achieving good water resistance and impregnation-reinforcing property by crosslinking the polymers after film formation. For example, an aqueous emulsion has been proposed in which fine grains of a double structure (a core-shell structure), having a core part in which glycidyl group-containing monomers are polymerized and a shell layer in which carboxyl group-containing monomers are polymerized and a shell layer in which carboxyl group-containing monomers are polymerized, are contained in an aqueous medium and, after film formation, glycidyl groups and carboxyl groups are subjected to crosslinking reactions (Japanese Patent Publication No. 39025/88). In the meantime, another aqueous emulsion has been proposed in which amino group-containing monomers are used instead of the above-mentioned carboxyl group-containing monomers, and, after film formation, glycidyl groups and amino groups are subjected to crosslinking reactions (Japanese Provisional Patent Publication No. 73308/94).
Regarding the above-described aqeuous emulsions, however, there is a fear that crosslinking functional groups (glycidyl groups, carboxyl group and the like) existing inside the fine grains will crosslink each other at storage. In particular, such tendency is prominent in case of storage under a high temperature. For this reason, the molecular weight of the fine grains increases during the storage of the aqueous emulsions and fluidity deteriorates. As a result, films using such aqueous emulsions have disadvantages of poor permeability to base material and surface smoothness.
It is an object of the present invention to provide a one-part cold crosslinking emulsion composition which exhibits excellent storage stability with maintaining good crosslinking property and a method of manufacturing the same.